JavaScript 中的 ' 和 " 有什么区别？

Question

I saw this question and I am wondering about the same thing in JavaScript.

If you use the character ' or the character " when making strings in JavaScript, the application seems to behave the same. So what is the difference between these two characters?

The only advantage I have seen in using ' to build strings is that I can do stuff like:

var toAppend = '<div id="myDiv1"></div>';

Instead of:

var toAppend = "<div id=\"myDiv1\"></div>";

Is there any significant difference between them that I should be aware of?

Answer 1

They are equivalent for all intents and purposes. If you want to use either one inside a string, it is a good idea to use the other one to create the string, as you noted. Other than that, it's all the same.

Answer 2

Although not technically a difference in Javascript, its worth noting that single quoted strings are not valid JSON , per se. I think that people automatically assume that since JSON is valid JS, that valid JS strings are also valid JSON, which isn't necessarily true .

Eg, {'key': 'Some "value"'} is not valid JSON, whereas {"key": "Some 'value'"} is.

Answer 3

There's no difference. The reason for its existence is exactly what you mentioned

Answer 4

根据 Mozilla 的说法，好的做法是在 HTML 中使用“”（不能使用“”），而在 Javascript 中保留“”（“”和“”都可以无差别地使用）......

Answer 5

I think there is another difference. If you do the following

var str1 = 'The \' character';
var str2 = 'The " character';
var str3 = "The ' character";
var str4 = "The \" character";
document.write(str1.replace("'", "%26"));
document.write(str2.replace('"', "%22"));
document.write(str3.replace("'", "%26"));
document.write(str4.replace('"', "%22"));

The document.write will fail for str1 and str4. That is the difference, but I don't know if there is a workaround to make them work.

Answer 6

Try this:

console.log("mama+"mama"")

Output : Uncaught SyntaxError: missing ) 
after argument list

Now try:

console.log('mama+"mama"')

Output :  mama+"mama"

They are equivalent! but sometimes you want to use "" inside a string, and that why we have '

Answer 7

As written above, there is no difference but for situation you need to use "/' inside a string.

I think a better practice for situation you need to concatenate strings with variables is using a template strings: Price: ${price}, Amount: ${amount}. Total: ${price*amount} Price: ${price}, Amount: ${amount}. Total: ${price*amount}

That's way you can add " and ', and concatenate variables.

Much easier to read, much easier to write.

Answer 8

WARNING!!!!

There is a difference. When adding to arrays, you have to use one or the other. The array gets confused when you use two different types of quotes.

Example:

//WILL NOT WORK
var array = ["apple","orange","banana"];

array.push('pear');

//WILL WORK
var array = ["apple","orange","banana"];

array.push("pear");